Many types of office buildings or other large commercial structures commonly have electrical wiring systems in metallic conduits or ducts that are embedded within the concrete floor in predetermined patterns for each floor area. With the advent of undercarpet wiring systems utilizing flat multiconductor cable and the attendant advantages in equipment layout flexibility and office planning, it is often desirable to interconnect the undercarpet wiring system to the existing conventional under-floor wiring system.
In making such interconnection, consideration is to be given to the grounding connection therebetween. Typically, the under-floor metallic ducts containing the electrical wires are suitably connected to ground. It is common practice in the art to provide grounding connection of standard electric outlet boxes and receptacle housings to the grounded under-floor ducts by means of a threaded conduit nipple through which the electrical wires in the duct may be passed for external connection. While the use of such a nipple provides grounding of the outlet box or housing, further connection is generally required to a grounded circuit of the receptacle. Such connection has been made in the art by means of a separate jumper wire for connecting the grounded outlet box and the grounded circuit of the receptacle. It is desirable to provide an interconnection apparatus having provision for establishing a suitable ground connection and a minimum number of parts which can be efficiently manufactured and readily assembled.